[webkit-help] tryFastMalloc usage

Zoltan Horvath zoltan at webkit.org
Wed Mar 28 00:32:35 PDT 2012


currently WebKit supports usage either of system-malloc or TCmalloc. It  
depends on your platform whether USE_SYSTEM_MALLOC macro is defined to 1  
or not.
By default WebKit builds with TCmalloc, but you can pass --system-malloc  
option to build-webkit and it will set the macro for you to 1.

FastMalloc is only a wrapper, but you can find TCmalloc's implementation  
in FastMalloc.cpp.



On Wed, 28 Mar 2012 01:50:24 +0200, Fabrice Robinet <cmg473 at motorola.com>  

> Hi group,
> In short: I wonder where tryFastMalloc should be used, and what's  
> *really*
> implemented in it (or should be).
> Longer story:
> According to the .cpp, it is supposed to use a cache, which would justify
> the "fast" in the function name.
> From FastMalloc.cpp
> // A malloc that uses a per-thread cache to satisfy small malloc  
> requests.
> // (The time for malloc/free of a small object drops from 300 ns to 50  
> ns.)
> But looking at the current source tryFastMalloc looks to just wrap
> malloc. (I just updated Chromium and thus WebCore too...),
> I have seen tryFastMalloc used in WebCore code that is not too old (like
> WebGL),
> so I believe it is not deprecated and *should* be used, so this raises a
> couple of questions:
> Is current state of tryFastMalloc temporary in the sense that a cache  
> will
> be used eventually ?
> Did I miss something about this cache in the implementation ?
> Are there (updated) guidelines about the usage of tryFastMalloc ?
> Thanks,
> Fabrice.

More information about the webkit-help mailing list